1. Field of the Invention
The present invention relates to a sensor device, which performs communication of data and supply/reception of drive electric power without contact, and containers having the same.
2. Description of the Related Art
Most of the products commercially available such as foods, medicines, and materials of the same are preserved in airtight containers to maintain safety, hygiene, and quality thereof. For example, some fresh foods or soft drinks are transported by vehicles in which the temperature of trunks can be controlled so that freshness can be preserved. Some medicines or foods lose their value as products once containers in which products are preserved are opened. That is, there is a case where confidence in the products' safety may be diminished.
However, there is a problem in that consumers purchasing goods at the retail stage cannot know accurately how the products have been managed in the distribution process. For example, consumers cannot easily determine whether the descriptions of the label on the products are true or not, even when the descriptions have been falsified.
A method for identification and certification using minute IC chips to manage products has received attention. IC chips are connected to antennas, or antennas are formed on IC chips to transmit and receive signals through wireless communication. With IC chips attached to tags or labels on products after identifiable information and the like is stored therein, this certification method is expected to perform effective management using computers. Information stored in IC chips is read by wireless communication using external devices called reader/writers. At this time, electric power needed for the operation of IC chips is covered by induced electromotive force generated from electromagnetic waves, which is outputted from external devices.
In addition, operating IC tags actively instead of using them only for certification is now under consideration. For example, an IC tag, which enables wireless communication with an external device to which a sensor capable of measuring the physical quantity of an object is attached, is disclosed (see Reference 1: Japanese Published Patent Application No. 2001-187611). The IC tag with the sensor includes a battery chargeable with electromagnetic waves for electric power, which is supplied from the external device as well as a communication portion, a CPU, and a temperature sensor.